Quinone-based compounds have a variety of biological activities. Some of them have been shown to have anti-cancer and other activities. For example, several natural occurring naphtho[2,3-b]furan-4,9-diones with interesting biological activities have been isolated from plants (Tisler, M. “Heterocyclic Quinones in Advances in Heterocyclic Chemistry” Vol. 45, ed. Katritzky, A. R., Academic Press, London, 1989, pp. 56-63), and 2-substituted naphtho[2,3-b]furan-4,9-diones have been found to have cytotoxic activity (Ogawa et al. Bioscience, Biotechnology, and Biochemistry, 2006, 70, 1009-1012).
As cancer is a leading cause of death worldwide, accounting for 13% of all deaths according to 2004 World Health Organization statistics, there remains a need for novel compounds useful for more effective treatment of cancer.